Electric motor and switching unit therefor

ABSTRACT

The invention relates to an electric motor (2) comprising a switching unit (8) having a number of contact wires (24) arranged in relation to a connection ring (22) for coil ends of a stator winding, and comprising an annular frame part (28) having a number of sockets (30) into each of which an insulation-displacement contact (14) with an insulation-displacement slot (52) can be inserted or is inserted, between two insulation-displacement limbs (54) for making terminal contact with at least one w ire end (26) of the contact wires (24), said sockets (30) each comprising a socket slot (38), on opposing socket walls (36), which is flush with the insulation-displacement slot (52) of the insulation-displacement contact (14) plugged into said socket (30), and the two socket walls (36) of each socket (30) each have a first clamping contour (42) protruding into the socket slot (38), for each wire end (26) received in the socket slot (38).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase of PCT/EP2018/083035 filedon Nov. 29, 2018, which claims priority to German Patent Application No.DE 10 2017 222 076.7, filed on Dec. 6, 2017, the disclosures of whichare hereby incorporated in their entirety by reference herein.

TECHNICAL FIELD

The present disclosure relates to an electric motor, such as an electricmotor for use in a motor vehicle.

BACKGROUND

A brushless electric motor has a stator with a number of stator teethwhich are arranged, for example, in a star shape and which support anelectric stator winding (motor winding) in the form of individual statorcoils, which are in turn wound from an insulating wire. The coils areassociated with individual phases by way of their coil ends and aremutually interconnected in a predetermined manner via connectingconductors of a switching unit, wherein the connecting conductors areformed, for example, as contact wires arranged annularly to form aninterconnecting ring.

In the case of a brushless electric motor as a three-phase AC machine,the stator has three phases and therefore at least three connectingconductors, to which an electric current is applied in a phase-shiftedmanner in each case in order to generate a magnetic rotating field inwhich a rotor, conventionally provided with permanent magnets, rotates.The connecting conductors are routed to motor electronics forcontrolling the electric motor. The coils of the stator winding areinterconnected with one another in a specific manner by means of theconnecting conductors. The type of interconnection is determined by thewinding pattern of the stator winding, wherein a star connection or adelta connection of the coils is the conventional winding pattern.

SUMMARY

The present disclosure may address one or more objects such as providingan electric motor having a reliable connection and contacting of itscontact wires.

In one or more embodiments, the electric motor may include a switchingunit with a number of contact wires arranged to form an interconnectingring for coil ends of a stator winding, and with an annular frame part.In this case, the frame part may include a number of insertion pockets,into which a respective insulation displacement contact with aninsulation displacement slot between two insulation displacement limbscan be inserted or is inserted for establishing clamping contact with atleast one wire end of the contact wires. In other words, the, or each,insulation displacement contact may include the two mutually spacedinsulation displacement limbs in each case to form the insulationdisplacement slot, wherein the insulation displacement slot is open onthe side of the free ends of the insulation displacement limbs. Onfacing pocket walls, the insertion pockets furthermore have a respectivepocket slot which is flush with the insulation displacement slot of theinsulation displacement contact inserted into this insertion pocket. Theinsulation displacement slot and the pocket slot may extend axially,i.e. parallel with respect to a motor shaft. In this case, the pocketwalls may define or form a clamping receptacle in which the insulationdisplacement contact is received in the course of the installationprocedure. The number of insertion pockets or insulation displacementcontacts may correspond to the number of phase connections of theelectric motor.

According to one or more embodiments, both pocket walls of therespective insertion pocket which have the pocket slot furthermore havea respective first clamping contour, extending into the pocket slot, foreach wire end received in the pocket slot.

The insulation displacement limbs have, on mutually facing sides, atleast one region constructed in the manner of a blade so that a wire endintroduced into the insulation displacement slot via the slot opening iscut and/or cut into and its wire insulation is thereby severed. In thiscase, the flexible insulation displacement limbs may exert a spring-likeclamping force on the respective wire end (the respective wire). In theinsulation displacement state of the wire or wire end, the blade edgesof the insulation displacement limbs extend virtually tangentially tothe conventionally approximately circular wire diameter.

The wire end to be contacted or the wire ends (wires) to be contactedmay be already introduced into the pocket slots in the course of theinstallation procedure when the insulation displacement contact isinserted into the associated insertion pocket. In this way, the, oreach, wire end received in the pocket slot may be aligned and secured bythe clamping contour in such a way that the inserted wire ends areorientated substantially perpendicular to a plane which is defined by(spans) the clamping receptacle and a bending of the wire end in theinsertion pocket is prevented or at least reduced. As a result of bothpocket walls each having a first clamping contour, such an alignment ofthe, or each, wire end is improved, and the bending thereof is furtherreduced. In this way, a comparatively uniform and reliable contacting ofthe respective wire at its two flanks by the two insulation displacementlimbs of the corresponding insulation displacement contact is realized.

In this case, a (clamping) force securing the wire end or the wire endsshould not be so great that the pressing-in of the insulationdisplacement contact in the course of the installation procedure ishindered and/or the wire end or the wire ends are not bent during theirintroduction into the insertion pocket, such as during the windingprocess. The wire end or the wire ends are clamped in the first clampingcontour such as a result of an at least slight deformability ofinsulation encompassing the wire and of the wire end itself. In thiscase, the clamping force is determined, or can be determined, such as,by the shape of the first clamping contour and by the depth to whichthis extends into the pocket slot and depending on the wire diameter andthe thickness of the insulation of the wire end.

According to one or more embodiments, the first clamping contour of therespective pocket wall may be arranged on the two clamping sides thereofwhich flank the pocket slot. In other words, the first clamping contouris arranged on the two clamping sides of the respective pocket wall. Theclamping sides refer to those sides of a pocket wall which adjoin thepocket slot, for example along the longitudinal slot direction, andtherefore likewise the wire end(s) introduced into the slot. In thisway, the, or each, wire end received in the slot is aligned centrallywith respect to the pocket slot. Consequently, the wire end or the wireends are also arranged centrally with respect to the insulationdisplacement slot which is formed by the insulation displacement limbs.Therefore, the wire end or the wire ends are advantageously stripped andcut comparatively uniformly, whereby the contacting reliability is inturn increased.

According to another embodiment, a projection which features a dome-likeelevation and may include a dome slot is arranged on the outside of oneof the pocket walls, which dome slot is flush with the pocket slot. Inthis case, the outside is that side of the pocket wall which is oppositethe clamping receptacle. In a suitable embodiment, the sides flankingthe dome slot have a second clamping contour, which may include a shapeanalogous to the first clamping contour, for example. The, or each, wireend is therefore aligned and secured by the sides of the projectionwhich flank the dome slot. In this way, a bending of the, or each, wireend within the clamping pocket is further reduced.

According to yet another embodiment, the first and additionally oralternatively the second clamping contour is formed as a rib or as a ribpair, which extends in the longitudinal direction of the pocket slot. Inan alternative embodiment, the clamping contour may include a diamond orhoneycomb shape, which extends over the entire side or sides flankingthe corresponding slot.

At least two wire ends may be received in one of the pocket slots andconnected to the corresponding insulation displacement contact. In thisway, for example, two or more contact wires are contacted by thecorresponding insulation displacement contact, i.e. electricallyconnected to one another, so that all associated contact wires can be orare connected to a phase connection of the electric motor by merely oneof the insulation displacement contacts.

To this end, the insulation displacement slot of the, or each,insulation displacement contact may include, in the longitudinal slotdirection, a first slot region adjoining a slot opening on the side ofthe free end of the limb and a widened second slot region adjoining thefirst slot region. For example, the second slot region is widened in adiamond or rhombus shape.

In the course of the installation procedure, a first wire end, in thecontacting process, is firstly pushed into the insulation displacementcontact and cut. In this case, the wire diameter of the wire end isreduced in the region of the insulation displacement edges. The widenedsecond region of the insulation displacement slot may receive the wireend which is firstly cut in the insulation displacement slot as soon asa second wire end arrives between the insulation displacement limbs,formed as blade edges, of the comparatively short or narrow first(cutting) region which may adjoin the slot opening. Since, in thisposition, the first wire end is located in the widened region of theinsulation displacement slot, the necessary insulation displacementforces of the two insulation displacement limbs act on the second wireend in the cutting region situated upstream towards the slot opening.The same applies to further wire ends introduced into the insulationdisplacement slot. In this case the, or each, wire end is orientatednormally to the slot plane of the insulation displacement contact.Furthermore, in this case, the wire diameter of those wire ends whichhave been introduced into the insulation displacement slot after thefirst wire end are cut or reduced successively by a smaller amount ineach case. In other words, the wire surface used for contactingdecreases successively.

According to one or more embodiments, the, or each, insulationdisplacement limb of the respective insulation displacement contact hasat least one raised joining contour on the outside of the limb, i.e. onthe side remote from the insulation displacement slot. This joiningcontour may cooperate with the two pocket walls of the correspondinginsertion pocket which are not slotted. The joining contour depending onits shape advantageously enables a force- and/or form-fitting seat ofthe insulation displacement contact within the insertion pocket. By wayof example, grooves, ribs, hooks and/or studs are integrally molded forthis purpose, incorporated for example via a stamping technique, and mayenable the force and/or form fit with corresponding mating piecesarranged on the associated pocket wall.

With regard to the switching unit, this has a number of contact wiresfor interconnecting coils of a stator winding with phase connections. Inthis case, these phase connections are each formed by an insulationdisplacement contact or may include these insulation displacementcontacts, wherein these can be inserted or are inserted into arespective insertion pocket of a frame part. By way of example, threeinsulation displacement contacts are provided for the contacting of thephase connections and are arranged equidistantly from one another.

For establishing the contact between the corresponding wire end or thecorresponding wire ends of the contact wires and the associatedinsulation displacement contact, the, or each, wire end is received inthe pocket slots of the mutually facing pocket walls of the insertionpocket. In this case, the, or each, wire end is secured by two firstclamping contours of both pocket walls, for example, to generatecomparatively reliable contacting.

The brushless oil pump motor of a motor vehicle has an electric motor inone of the variants described above. Therefore, the oil pump motor has,for example, a switching unit with a frame part, which in turn mayinclude a number of insertion pockets for receiving insulationdisplacement contacts by means of a respective pocket slot on facingpocket walls. In this case, each of the two pocket walls of the, oreach, insertion pocket has a first clamping contour projecting into thepocket slot.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are explained in more detailbelow with reference to a drawing, which shows:

FIG. 1 in a perspective illustration, an electric motor with a stator,which is seated on a switching unit, and with a rotor and withelectronics which are connected to an interconnecting ring by insulationdisplacement contacts,

FIG. 2 in a perspective illustration, the switching unit with an annularframe part and with the interconnecting ring, wherein this latter has aplurality of contact wires arranged in a circle and wherein two wireends of the interconnecting ring in each case are connected to theinsulation displacement contacts inserted into insertion pockets of theframe part,

FIG. 3a in a plan view, an insertion pocket according to the prior art,wherein two of its mutually facing pocket walls each have a pocket slot,in which a wire end is received eccentrically with respect to the pocketslot,

FIG. 3b in a plan view, the insertion pocket designed according to theinvention, whereof the pocket walls having the pocket slots each have afirst clamping contour extending into the corresponding pocket slot anda dome-like projection which is arranged on the outside of one of thepocket walls and whereof the dome slot is flush with the correspondingpocket slot,

FIG. 3c in a plan view, the insertion pocket according to FIG. 3b with awire end received therein,

FIG. 3d in a front view, the insertion pocket according to FIG. 3b withtwo wire ends received therein, which are each contacted by one of theinsulation displacement contacts, and

FIG. 4 in a perspective illustration, an insulation displacement contactwith an insulation displacement slot, which is flanked by two insulationdisplacement limbs and which has a widened slot region.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

Mutually corresponding parts are denoted by the same reference signs inall figures.

DE 101 52 006 A1 discloses a stator with an annular stator yoke on whichstator coils with coil ends and an interconnecting arrangement withconnecting conductors are arranged. Receiving elements for connectionsof the connecting conductors are furthermore formed on the stator, whichreceiving elements each have a receiving means formed as a slot for thecoil ends. In this case, the connections of the connecting conductorsare realized as insulation displacement terminations and form anelectric insulation displacement connection in pairs with the coil endsat the associated receiving elements.

WO 2016/124636 A1 discloses an electric motor with a switching unit witha number of contact wires and with an annular frame part, in which thecontact wires are arranged to form an interconnecting ring for the coilends of a stator winding and wire ends of the contact wires areconnected to insulation displacement contacts. The insulationdisplacement contacts each have two mutually spaced insulationdisplacement limbs, forming an insulation displacement slot, for theconnection of at least two of the wire ends, wherein the frame part ofthe switching unit has a number of insertion pockets, corresponding tothe number of insulation displacement contacts, for receiving theinsulation displacement contacts.

The contact wire to be connected to the insulation displacement contactis provided with insulating sheathing (insulation). When establishingsuch an insulation displacement connection, the wire or its wire end ispressed into a slot in the insulation displacement contact so that theblade-like insulation limbs of the insulation displacement contact,which flank the slot, sever the insulation at the corresponding pointsand cut into the wire circumferentially. In this case, it is possiblethat the wire, for example as a result of wire bending, is not seatedcentrally in the slot during the pressing-in process, so that one sideof the wire is cut into to a comparatively lesser extent during thepressing-in of the insulation displacement contact, or the insulation isactually only stripped on one side. Therefore, only a comparativelysmall wire surface is used for contacting purposes.

When more than one wire end is connected to an insulation displacementcontact, these wires can have different diameters, in particular as aresult of strain thereon. As a result, a non-central alignment of thewires is promoted when the wires are pressed in successively, whichagain means that only a comparatively small wire surface can be used forcontacting purposes.

In this case, the insertion pockets receiving the insulationdisplacement contacts have, on their mutually facing pocket walls, arespective pocket slot for receiving the wire. It is known from DE 102013 114 688 A1 and from DE 20 2010 016 199 Ul that a holding contourfor the corresponding wire end is arranged on one of the two pocketwalls. It is furthermore known from DE 10 2013 114 688 A1 that, to alignthe wire, a centering prism is formed in an end region of the bearingsurface of the pocket slot.

00361 FIG. 1 shows an electric motor 2 such as a brushless oil pumpmotor for a motor vehicle. The electric motor 2 has a rotor 4 and amotor shaft 6 and a stator 10 provided with a switching unit 8. Theelectric motor 2 furthermore has a printed circuit board (electronics)12, which is contacted by three insulation displacement contacts 14 viatheir contact heads 16. In the installed state, the contact heads 16are—according to this exemplary embodiment inserted into crimped-lugtype insertion receptacles 18 of contacts (flat contacts) or contactportions 20 produced, for example, as punched and bent parts from flatwire. In this case, the contact heads 16 in FIG. 1 are shown removedfrom the corresponding insertion receptacles 18 in the manner of anexploded illustration for better visualization. The insulationdisplacement contacts 14 here form the phase connections for thethree-phase energization of the stator or motor winding.

FIG. 2 shows the switching unit 8 with an interconnecting ring 22. Thishas a plurality of contact wires 24 arranged in a circle. In this case,two wire ends 26 of the contact wires 24 in each case are contacted byone of the three equidistantly arranged insulation displacement contacts14.

The switching unit 8 furthermore has an annular frame part 28, which isformed, for example, from plastic. This in turn has, in the region ofthe respective insulation displacement contact 14, an insertion pocket30 for receiving the insulation displacement contact 14.

Furthermore, in FIG. 2, the switching unit 8 is illustrated withcomplete, closed coil cassettes 32, which are integrally molded on theframe part 28 of the switching unit 8. These receive the stator teeth ofthe electric motor 2 in its installed state and are wound with theindividual coils of the stator winding in a manner not illustrated infurther detail.

FIG. 3a shows an insertion pocket 30 according to the prior art. Thishas a clamping receptacle 34, in which the corresponding insulationdisplacement contact 14 will be or is received. In this case, theclamping receptacle 34 is encompassed circumferentially by pocket walls36, wherein a respective pocket slot 38, in which the wire end 26 isreceived, is arranged on two mutually facing pocket walls 36. In thiscase, the two pocket slots 38 are flush with one another. The receivedwire end 26 has a bend and is not arranged centrally with respect to thepocket slot 38.

FIG. 3b shows the pocket slot 30, according to one or more embodiments,with a clamping receptacle 34, which is encompassed by pocket walls 36.Two mutually facing pocket walls 36 each have a pocket slot 38. In thiscase, the clamping sides 40, flanking the pocket slots 38, of thecorresponding pocket walls 36 each have a first clamping contour 42.

Furthermore, a projection 44, which features a dome-like elevation andhas one of the pocket slots 38, is arranged on the outside of one of thepocket walls 36, which projection is integrally molded on this pocketwall 36 according to this exemplary embodiment. This projection 44 inturn has a dome slot 46, which is flush with the pocket slots 38,wherein the sides 48 flanking the dome slot 46 each have a secondclamping contour 50. The first clamping contour 42 and the secondclamping contour 50 are formed as ribs here, which extend along alongitudinal direction L (FIG. 3d ) of the pocket slot 38 and the domeslot 48. In FIGS. 3b and 3c , the longitudinal direction L extends intothe plane of the drawing.

FIG. 3c shows the insertion pocket 30 of FIG. 3b , wherein one of thewire ends 26 of the contact wires 24 is received therein. In contrast toFIG. 3a , it can be seen that the wire end 26 is aligned and secured, inparticular clamped (trapped), centrally with respect to the two mutuallyflush pocket slots 38 by means of the first clamping contour 42 andadditionally by means of the second clamping contour 50. As a result ofthis, the bending of the wire end 26 is additionally prevented or atleast comparatively greatly reduced.

According to FIG. 3d , two wire ends 26 are received in the insertionpocket 30 and contacted by the corresponding insulation displacementcontact 14. In this case, in the installed state of the insulationdisplacement contact 14 in this insertion pocket 30, an insulationdisplacement slot 52, which is formed between two insulationdisplacement limbs 54 of the insulation displacement contact 14 (FIG.4), is flush with the pocket slots 38 of the insertion pocket and thedome slot 46. Then, owing to the two wire ends 26 being securedcentrally in the pocket slot 38 during the pressing-in of the associatedinsulation displacement contact 14, the wire end 26 is advantageouslycut uniformly by the blade-like insulation displacement limbs 52 in thecourse of its installation and may provide reliable contacting of thewire end 26 by the insulation displacement contact 14 is thus achieved.

According to a further variant (not illustrated further) of theinsertion pocket according to the invention, a projection 44 is notarranged on thereon. The wire ends 26 are then secured merely by meansof the first clamping contours 42.

According to a further variant (not illustrated further), the insertionpockets 30 of the frame part 28 shown in FIG. 2 each have a projection44 with a second clamping contour 50 according to FIGS. 3b to 3 d.

FIG. 4 shows one of the insulation displacement contacts 14 with aninsulation displacement slot 52 which is flanked by two insulationdisplacement limbs 54 of the insulation displacement contact 14, i.e. itis located or formed between these two insulation displacement limbs 54.The insulation displacement contact 14 is may be a punched part. Theinsulation displacement limbs 54 of the insulation displacement contact14 may merge into the contact head 16, which is may be provided with athrough-opening (through-bore) 56. Joining contours 58 (grooves, studs)may be integrally molded or stamped on the outside of the insulationdisplacement limbs 54.

The insulation displacement slot 52 has a slot opening 60 in the regionof the free ends of the insulation displacement limbs 54. A first,comparatively short, slot region 62 adjoins this in the longitudinalslot direction S. This slot region merges into a widened second slotregion 64 in the longitudinal slot direction S. This second slot regionmay be diamond shaped. A third, comparatively long insulationdisplacement region, or at least a clamping region 66, in turn adjoinsthis region 64. This region 66 terminates at the ends which are oppositethe free ends of the limbs, i.e. at the merging region 68 of theinsulation displacement limbs 54.

As a result of this contact geometry, reliable contacting or connectionof not only one wire end, but two or more wire ends, is enabled. Theseare inserted or pressed successively into the insulation displacementslot 52 in the longitudinal slot direction S and thereby cutcircumferentially (azimuthally). The cutting depth in this case isgreater than or equal to the thickness of the insulation (insulatingsheath) of the, or each, wire end. To this end, the mutually facingedges of the insulation displacement limbs 54 are designed in the mannerof a blade, as blade edges 68, in the region of the insulationdisplacement slot 52.

The invention is not restricted to the exemplary embodiments describedabove. Rather, the person skilled in the art is also able to deriveother variants of the invention from these, without deviating from thesubject matter of the invention. In particular, all individual featuresdescribed in association with the exemplary embodiments can furthermorealso be combined with one another in a different way without deviatingfrom the subject matter of the invention.

The following is a list of reference numbers shown in the Figures.However, it should be understood that the use of these terms is forillustrative purposes only with respect to one embodiment. And, use ofreference numbers correlating a certain term that is both illustrated inthe Figures and present in the claims is not intended to limit theclaims to only cover the illustrated embodiment.

LIST OF REFERENCE SIGNS

-   -   2 Electric motor    -   4 Rotor    -   6 Motor shaft    -   8 Switching unit    -   10 Stator    -   12 Printed circuit board    -   14 Insulation displacement contact    -   16 Contact head of an insulation displacement contact    -   18 Insertion pocket    -   20 Contact portion    -   22 Interconnecting ring    -   24 Contact wire    -   26 Wire end    -   28 Frame part    -   30 Insertion pocket    -   32 Coil cassette    -   34 Clamping receptacle    -   36 Pocket wall    -   38 Pocket slot    -   40 Clamping side    -   42 First clamping contour    -   44 Dome-like projection    -   46 Dome slot    -   48 Side flanking the dome slot    -   50 Second clamping contour    -   52 Insulation displacement slot    -   54 Insulation displacement limb    -   56 Through-opening    -   58 Joining contour    -   60 Slot opening    -   62 First slot region    -   64 Second slot region    -   66 Insulation displacement region    -   68 Blade edge    -   L Longitudinal direction of the pocket slot    -   S Longitudinal slot direction

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

1. An electric motor comprising: a switching unit provided with a numberof contact wires, arranged to form an interconnecting ring for coil endsof a stator winding and an annular frame part including, a number ofinsertion pockets including a first pocket wall and a second pocket wallfacing the first pocket wall, wherein the first pocket wall and thesecond pocket wall define a pocket slot, an insulation displacementcontact, provided with two insulation displacement limbs defining aninsulation displacement slot disposed between the two insulationdisplacement limbs, inserted into an insertion pocket of the number ofinsertion pockets to form a clamping contact between a wire end of acontact wire of the number of contact wires, wherein the pocket slot ispositioned flush to the insulation displacement slot and the firstpocket wall and the second pocket wall each define a first clampingcontour extending into the pocket slot and engaging the wire end.
 2. Theelectric motor of claim 1, wherein one of the pocket walls of the firstand second pocket walls includes a first clamping side and a secondclamping side each flanking the pocket slot and defining the firstclamping contour.
 3. The electric motor of claim 1, wherein the annularframe part includes a dome-shaped projection disposed on an outer sideof one of the pocket walls and defining a dome slot arranged flush withthe pocket slot.
 4. The electric motor of claim 3, wherein thedome-shaped projection forms a second clamping contour flanking the domeslot.
 5. The electric motor of claim 4, wherein the first pocket walland/or the dome-shaped projection include a number of ribs that form thefirst clamping contour and/or the second clamping contour, respectively,wherein at least one of the ribs of the number of ribs extends in alongitudinal direction defined by the pocket slot.
 6. The electric motorof claim 1, wherein one of the pocket slots receives at least two wireends, of the number of contact wires, connected to the insulationdisplacement contact.
 7. The electric motor of claim 1, wherein theinsulation displacement slot includes first slot region and a secondslot region each extending in a longitudinal slot direction defined bythe insulation displacement contact, wherein the first slot region isdisposed on a side of a free end of the insulation displacement contactand adjoins a slot opening defined by the insulation displacementcontact, and wherein the second slot region is wider than the first slotregion and adjoins the first slot region.
 8. The electric motor of claim1, wherein the insulation displacement contact includes a limb providedwith at least one raised joining contour extending from an outer surfaceof the limb.
 9. A switching unit for use in an electric motor, theswitching unit comprising: a number of contact wires each configured tointerconnect coils of a stator winding; a number of phase connectionsformed by a number of insulation displacement contacts; a frame partdefining a number of insertion pockets, wherein a first insertion pocketof the number of insertion pockets includes a number of pocket wallsdefining a pocket slot and a first clamping contour, wherein the firstclamping contour secures a number of wire ends of the number of contactwires disposed in the pocket slot, wherein at least a portion of a firstinsulation displacement contact of the number of insulation displacementcontacts is inserted into the pocket slot so that the first insulationdisplacement contact contacts a first wire end of the number of wireends.
 10. A brushless oil pump motor for use in a motor vehicleincluding the switching unit of claim
 9. 11. The switching unit of claim9, wherein the number of phase connections equals the number ofinsertion pockets.
 12. The switching unit of claim 9, wherein the firstclamping contour extends into the first pocket slot.
 13. The switchingunit of claim 9, wherein the number of pocket walls collectively definea clamping receptacle orthogonal to the pocket slot.
 14. The switchingunit of claim 9, wherein the clamping receptacle intersects the pocketslot.
 15. The switching unit of claim 9, wherein the frame part includesdome-shaped projection at least partially surrounding the firstinsertion pocket.
 16. The switching unit of claim 15, wherein thedome-shaped projection defines a dome slot disposed adjacent to thepocket slot.
 17. The switching unit of claim 16, wherein a side flankingthe dome slot defines a second clamping contour is configured to engageone or more contact wires of the number of wire ends.
 18. The switchingunit of claim 17, wherein the first clamping contour and the secondclamping contour are aligned with one another with respect to the pocketslot to prevent bending of at least one of the contact wires engaged bythe first clamping contour and the second clamping contour.
 19. Theswitching unit of claim 9, wherein the insulation displacement contactincludes a first limb and a second limb collectively defining a slotopening receives the first wire end and a second wire end of the numberof wires ends and disposed on top of the first wire end.
 20. Theswitching unit of claim 19, wherein the first limb and the second limbeach include a distal end defining a first slot region and a second slotregion, wherein the first slot region is tapered with respect to thesecond slot region.